1. Field of the Description
The present description relates, in general, to apparatus for simulating a human or human-like eye such as a robotic or animatronic eye or a prosthetic eye (all considered “artificial” eyes), and, more particularly, to an animatronic or prosthetic eye assembly that utilizes fluid-immersion and is electromagnetically driven.
2. Relevant Background
Animatronics is widely used in the entertainment industry to bring mechanized puppets, human and human-like figures, and other characters to life. Animatronics is generally thought of as the use of electronics and robotics to bring inanimate objects alive. Animatronics are used in moviemaking to provide realistic and lifelike action in front of the camera as well as in other entertainment settings such as in theme parks, e.g., to provide lifelike characters in a theme ride or a show. Animatronics are often used in situations where it may be too costly or dangerous for a live actor to provide a performance. Animatronics may be computer controlled or manually controlled with actuation of specific movements obtained with electric motors, pneumatic cylinders, hydraulic cylinders, cable driven mechanisms, and other components that are chosen to suit the particular application including the show or ride setting or stage and the specific character parameters and movement requirements.
In the field of animatronics, there is a continuing demand to provide animatronic characters that better imitate humans and animals. Specifically, much of human and human-like character expression and communication is based on their eyes, including eye contact, eye movement, and gaze direction. With this in mind, designers of robotic and other artificial eyes attempt to mimic the subtle movements and appearance of the human eye to make animatronic figures more lifelike, believable, and engaging. Animatronic designers often have trouble accurately replicating human eye appearance and movement. Challenges arise due to the need for rotation of the eye in a socket in a relatively rapid and smooth manner and also due to the relatively small form factor of the eye in an animatronic figure.
Many types of robotic or animatronic eyes have been created with a number of actuating mechanisms. To actuate or rotate the eye, a drive or actuating mechanism is provided adjacent the eye such as in the animatronic figure's head that includes external motors, hydraulic cylinders, gears, belts, pulleys, and other mechanical drive components to drive or move a spherical or eye-shaped orb. As a result, the eye assemblies require a large amount of external space for their moving parts, and space requirements have become a major issue as the eye itself is often dwarfed by the mechanical equipment used to move the eye up and down (e.g., tilt or pitch) and side-to-side (or yaw). The mechanical drive equipment has moving components external to and attached to the eye that need mounting fixtures and space to freely move. In some cases, existing animatronic eye designs are somewhat unreliable and require significant amounts of maintenance or periodic replacement due, in part, to wear caused by friction of the moving parts including the eye within a socket device. To retrofit an eye assembly, the electromechanical, pneumatic, hydraulic, or other drive or eye-movement systems typically have be completely removed and replaced.
In some cases, animatronic eyes cannot perform at the speeds needed to simulate human eye movement. Movements may also differ from smooth human-like action when the drive has discontinuous or step-like movements, which decreases the realism of the eye. Additionally, many animatronic eye assemblies use a closed loop servo control including a need for a position or other feedback signal such as from optical, magnetic, potentiometer or other position sensing mechanisms. Further, the eye or eyeball's outer surfaces may rub against the seat or socket walls since it is difficult to provide a relatively frictionless support for a rotating sphere or orb, which may further slow its movement, cause wear on painted portions of the eyeball, or even prevent smooth pitch and yaw movements.
More recently, an animatronic eye was created that made use of fluid suspension and an electromagnetic drive, i.e., an eye assembly described in U.S. Pat. No. 8,715,033. The eye assembly includes a spherical, hollow outer shell that contains a suspension liquid. An inner sphere is positioned in the outer shell in the suspension liquid to be centrally floated at a distance away from the shell wall. The inner sphere includes painted portions providing a sclera and iris and includes an unpainted rear portion and front portion or pupil. The shell, liquid, and inner sphere have matching indices of refraction such that interfaces between the components are not readily observed. A drive assembly is provided including permanent magnets on a surface of the inner sphere that are driven by electromagnetic coils located on an external surface of the outer shell.
This animatronic eye's operations were based on having an inner, plastic eye floating (i.e., neutrally buoyant) inside an outer, plastic, fluid-filled, and transparent outer shell. The inner eye or sphere had permanent magnets on its surface that were pulled around by electromagnetic coils on the outer surface of the outer plastic shell. The flotation technique provided extremely low friction, and, because the fluid index matched the inner plastic eye and the outer transparent shell, an illusion was created that the outer surface of the entire eye moved when only the inner eye or sphere actually was rotated.